U.S. patent application number 10/853658 was filed with the patent office on 2006-04-13 for method for manufacturing microstructures having hollow microelements using fluidic jets during a molding operation.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Vladimir Gartstein, Faiz Feisal Sherman.
Application Number | 20060076718 10/853658 |
Document ID | / |
Family ID | 33551524 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060076718 |
Kind Code |
A1 |
Sherman; Faiz Feisal ; et
al. |
April 13, 2006 |
Method for manufacturing microstructures having hollow
microelements using fluidic jets during a molding operation
Abstract
A method is provided for constructing microstructures that can
penetrate skin layers, in which the microelements are formed during
a molding process while fluidic jets produce openings in the
microelements. The structures used in the molding process are
formed by tooling that creates the shapes of the microelements in a
material deposition step, and also creates the sizes and shapes of
the openings that will be formed by the fluidic jets.
Inventors: |
Sherman; Faiz Feisal; (West
Chester, OH) ; Gartstein; Vladimir; (Cincinnati,
OH) |
Correspondence
Address: |
REED INTELLECTUAL PROPERTY LAW GROUP
1400 PAGE MILL ROAD
PALO ALTO
CA
94304-1124
US
|
Assignee: |
The Procter & Gamble
Company
|
Family ID: |
33551524 |
Appl. No.: |
10/853658 |
Filed: |
May 25, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60475085 |
Jun 2, 2003 |
|
|
|
Current U.S.
Class: |
264/504 ;
264/154; 264/219 |
Current CPC
Class: |
B29C 2043/023 20130101;
B29C 59/022 20130101; A61M 37/0015 20130101; A61M 2037/003
20130101; B29C 2793/0045 20130101; B29C 33/0033 20130101; B29C
2043/3233 20130101; B26F 1/26 20130101; A61M 2037/0053 20130101;
B29C 2059/023 20130101; B29C 33/3814 20130101; B29C 37/0053
20130101; B29C 33/3857 20130101 |
Class at
Publication: |
264/504 ;
264/154; 264/219 |
International
Class: |
B26D 3/00 20060101
B26D003/00; B29C 33/40 20060101 B29C033/40 |
Claims
1. A method for constructing a microstructure, said method
comprising: (a) providing a moldable material to be formed into a
predetermined shape; (b) during a molding procedure, forcing a
predetermined fluid under pressure toward a surface of said
moldable material, said predetermined fluid forming at least one
opening at said surface; and (c) substantially solidifying said
moldable material while said pressurized predetermined fluid
continues to flow toward said surface, thereby forming a solid
microstructure which includes said at least one opening at said
surface.
2. The method as recited in claim 1, wherein: said at least one
opening extends completely through said solid microstructure.
3. The method as recited in claim 1, wherein: said at least one
opening forms an indentation that does not extend completely
through said solid microstructure.
4. The method as recited in claim 1, wherein said molding procedure
comprises one of: (a) injection molding, (b) embossing, and (c) die
casting.
5. The method as recited in claim 1, further comprising: providing
a micromold having a first mold-half and a second mold-half, said
first mold-half including a plurality of openings through which
said predetermined fluid is forced under pressure.
6. The method as recited in claim 5, wherein: said second mold-half
comprises one of: (a) a material that is substantially non-porous
with respect to said moldable material, but is substantially porous
with respect to said predetermined fluid; and (b) a material that
is substantially non-porous with respect to said moldable material,
and is also substantially non-porous with respect to said
predetermined fluid.
7. The method as recited in claim 5, wherein: (a) said moldable
material is formed into a three-dimensional negative form of said
first and second mold-halves, and comprises (i) a substrate having
a first surface and a second surface opposite said first surface,
and (ii) at least one protrusion extending from the first surface
of said substrate; and (b) said at least one opening is physically
located at one of: (i) one of said at least one protrusion, and
(ii) along a substantially planar portion of the first surface of
said substrate.
8. The method as recited in claim 7, wherein: said at least one
protrusion exhibits a length in the range of 0.1-3000 microns.
9. A method for constructing a micromold, said method comprising:
(a) providing a tooling structure having a first surface and a
second surface opposite said first surface, and having a substrate
having a plurality of protrusions formed upon said first surface,
said plurality of protrusions exhibiting at least one height; (b)
depositing a material upon the first surface of said tooling
structure, said material having a thickness that is generally less
than said at least one height of said plurality of protrusions; and
(c) separating said material from said tooling structure to form a
micromold, said micromold exhibiting a first plurality of openings
that correspond to a portion of a three-dimensional negative form
of said plurality of protrusions of the tooling structure along
said thickness of said material.
10. The method as recited in claim 9, wherein said depositing step
comprises one of: (a) electroplating; (b) spin coating; and (c)
vapor deposition.
11. The method as recited in claim 9, further comprising: (d)
providing a backing member; (e) introducing a moldable material
between said micromold and said backing member; (f) during a
molding procedure, forcing a predetermined fluid under pressure
through said first plurality of openings in said micromold toward a
third surface of said moldable material, said predetermined fluid
forming a second plurality of (openings at said third surface; and
(g) substantially solidifying said moldable material while said
pressurized predetermined fluid continues to flow toward said third
surface, thereby forming a solid microstructure which includes said
second plurality of openings at said third surface.
12. The method as recited in claim 11, wherein, one of: (a) said
second plurality of openings extend completely through said solid
microstructure; (b) said second plurality of openings form at least
one indentation that does not extend completely through said solid
microstructure; and (c) a first group of the second plurality of
openings extends completely through said solid microstructure,
while a second group of the second plurality of openings forms at
least one indentation that does not extend completely through said
solid microstructure.
13. The method as recited in claim 11, wherein said molding
procedure comprises one of: (a) injection molding, (b) embossing,
and (c) die casting.
14. The method as recited in claim 11, further comprising: (h)
providing a mask member which exhibits a third plurality of
openings; (i) placing said mask member substantially against a
surface of said micromold that faces away from said backing member,
wherein by such placement, said third plurality of openings is
substantially well-aligned with said first plurality of openings of
said micromold; and (j) during said molding procedure, forcing said
predetermined fluid under pressure through both said third
plurality of openings of said mask member and said first plurality
of openings of said micromold toward said third surface of said
moldable material.
15. The method as recited in claim 14, wherein said mask member
exhibits one of the following physical characteristics: (a) said
mask member comprises a substantially flat plate; (b) said mask
member exhibits a shape similar to said micromold, but inverted in
orientation; and (c) at said surface between said mask member and
micromold, an inner area of the third plurality of openings of said
mask member is generally smaller than an inner area of the first
plurality of openings of said micromold.
16. The method as recited in claim 11, wherein: said backing member
comprises one of: (a) a material that is substantially non-porous
with respect to said moldable material, but is substantially porous
with respect to said predetermined fluid; and (b) a material that
is substantially non-porous with respect to said moldable material,
and is also substantially non-porous with respect to said
predetermined fluid.
17. The method as recited in claim 11, wherein: (a) said moldable
material is formed into a three-dimensional negative form of said
backing member and said micromold, and comprises: (i) a substrate
having said third surface and a fourth surface opposite said third
surface, and (ii) a second plurality of protrusions extending from
the third surface of said substrate; and (b) at least some of said
second plurality of openings are physically located at one of: (i)
one of said second plurality of protrusions, and (ii) along a
substantially planar portion of the third surface of said
substrate.
18. The method as recited in claim 17, wherein: said second
plurality of protrusions exhibits a length in the range of 0.1-3000
microns.
19. A method for constructing a microstructure, said method
comprising: (a) providing a tooling structure having a first
surface and a second surface opposite said first surface, and
having a first substrate having a plurality of protrusions formed
upon said first surface, said plurality of protrusions exhibiting
at least one height; (b) depositing a first material upon the first
surface of said tooling structure, said first material having a
thickness that is generally less than said at least one height of
said plurality of protrusions; (c) releasing said first material
from said tooling structure, said first material exhibiting a
plurality of openings that correspond to a portion of a
three-dimensional negative form of said plurality of protrusions of
the tooling structure along said thickness of said first material,
said plurality of openings exhibiting at least one predetermined
inner area proximal to a third surface of said first material; (d)
providing a backing member at a predetermined and spaced-apart
distance from a fourth surface of said first material, said fourth
surface being opposite said third surface of the first material,
said backing member exhibiting comparatively little porosity with
respect to a moldable second material, but exhibiting substantial
porosity with respect to a predetermined fluid; (e) introducing
said moldable second material between said backing member and the
fourth surface of said first material, and forcing said
predetermined fluid under pressure through said plurality of
openings of the first material to form at least one channel in said
second material between said first material and said backing
member, and substantially solidifying said second material while
said pressurized predetermined fluid continues to flow through said
plurality of openings; and (f) separating said solidified second
material from said backing member and said first material, said
solidified second material exhibiting a second substrate and
exhibiting a plurality of microelements that substantially
correspond in size and shape to a three-dimensional negative form
of said plurality of openings in the first material, and further
exhibiting said at least one channel running completely through
said second substrate and at least one of said plurality of
microelements.
20. The method as recited in claim 19, wherein said plurality of
openings are smaller in area proximal to said third surface than
they are in inner area proximal to said fourth.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/475,085, filed Jun. 2, 2003.
TECHNICAL FIELD
[0002] The present invention relates generally to manufacturing
microstructures and is particularly directed to microstructures of
the type which contain a substrate and an array of microelements
with through-holes. The invention is specifically disclosed as a
method for constructing microstructures that can penetrate skin
layers, in which the microelements are formed during a molding
process while fluidic jets produce openings in the microelements.
The structures used in the molding process are formed by tooling
that creates the shapes of the microelements, and also creates the
sizes and shapes of the openings that will be formed by the fluidic
jets. In some embodiments, the sizes and shapes of the openings are
determined by a mask plate, while in another embodiment, no
separate mask plate is used. In some embodiments, the molding
structures are formed using a deposition process, while in other
embodiments, they are formed by injection molding, embossing, or
die casting. In one of the embodiments, the microstructures are
formed by depositing a material onto the surface of a tooling of a
particular shape, and then after being released from the tooling,
placing a second material that acts as the mask over the first
tooling-formed material. A moldable material is then placed against
the combination of the two materials, and during this procedure a
high pressure gas or liquid is directed through the holes (i.e.,
forming the fluidic jets) in the mask to form through-holes in the
moldable material. Once the moldable material is released, the
result will be an array of hollow microelements that protrude from
a substrate. In one of the alternative embodiments (without the
separate mask), the first material has openings that will be of a
proper size for use themselves as a "mask" for the directed high
pressure gas or liquid.
BACKGROUND OF THE INVENTION
[0003] Microstructures containing an array of microelements have
been disclosed in various patent publications, many of which
include openings that allow a fluid exchange between the top and
bottom surfaces of the microelement array. The individual
microelements typically are designed to penetrate the stratum
corneum of animal skin, or to penetrate some other type of
membrane. Once the penetration has been accomplished, a fluid
(e.g., liquid drugs) can be dispensed into the body from a
reservoir in the microstructure, or in the reverse direction, a
body fluid can be sampled into such a reservoir in the
microstructure.
[0004] The proper size and shape of the microelements depends upon
many factors, and for some applications (e.g., drug delivery or
body fluid sampling through human skin), several different sizes,
and especially shapes, will suffice. Some applications of
microstructures do not require openings; however, for those
applications that do need openings, it is important to find a way
to manufacture such microstructures in an inexpensive (and
high-volume) manner, within tolerable accuracy to lower reject
rates during the manufacturing of these devices.
[0005] Various sizes and shapes of microstructures have been
disclosed by the present inventors, in commonly-assigned United
States Patent applications, as noted below. The documents listed
below are incorporated herein by reference, in their entirety:
INTRACUTANEOUS MICRONEEDLE ARRAY APPARATUS, U.S. Ser. No.
09/328,947, filed on Jun. 9, 1999; APPARATUS AND METHOD FOR USING
AN INTRACUTANEOUS MICRONEEDLE ARRAY, U.S. Ser. No. 09/329,025,
filed on Jun. 9, 1999, now U.S. Pat. No. 6,256,533 B1, which issued
Jul. 3, 2001; APPARATUS AND METHOD FOR MANUFACTURING AN
INTRACUTANEOUS MICRONEEDLE ARRAY, U.S. Ser. No. 09/328,946, filed
on Jun. 9, 1999, now U.S. Pat. No. 6,312,612 B1, which issued Nov.
6, 2001; INTRACUTANEOUS EDGED MICRONEEDLE APPARATUS, U.S. Ser. No.
09/580,780, filed on May 26, 2000; INTRACUTANEOUS MICRONEEDLE ARRAY
APPARATUS, U.S. Ser. No. 09/580,819, filed on May 26, 2000; METHOD
OF MANUFACTURING AN INTRACUTANEOUS MICRONEEDLE ARRAY, U.S. Ser. No.
09/579,798, filed on May 26, 2000; METHOD OF MANUFACTURING
MICRONEEDLE STRUCTURES USING SOFT LITHOGRAPHY AND PHOTOLITHOGRAPHY,
U.S. Ser. No. 09/808,534, filed on Mar. 14, 2001; MICROSTRUCTURES
FOR TREATING AND CONDITIONING SKIN, U.S. Ser. No. 09/952,403, filed
on Sep. 14, 2001; MICROSTRUCTURES FOR DELIVERING A COMPOSITION
CUTANEOUSLY TO SKIN, U.S. Ser. No. 09/952,391, filed on Sep. 14,
2001; MICROSTRUCTURES FOR DELIVERING A COMPOSITION CUTANEOUSLY TO
SKIN USING ROTATABLE STRUCTURES, U.S. Ser. No. 10/216,148, filed on
Aug. 9, 2002; and METHOD FOR MANUFACTURING MICROSTRUCTURES HAVING
MULTIPLE MICROELEMENTS WITH THROUGH-HOLES, U.S. Ser. No.
10/373,251, filed on Feb. 24, 2003.
[0006] It would be beneficial to provide an improved and low-cost,
high-volume method of manufacturing microstructures with openings
that extend through the substrate and through the individual
microelements.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is an advantage of the present invention to
provide a methodology for forming a microstructure having an array
of microelements with openings, in which the microstructure is
formed by first depositing a material on a tooling (such as a die
or mold) of a predetermined shape up to a predetermined thickness,
in which the tooling exhibits a plurality of protrusions that cause
openings to be created in the first material, then releasing the
first material and placing a second material thereupon which acts
as a mask over the first material, the mask having openings at
predetermined locations, then placing a moldable (third) material
against a surface formed by both of the first material and second
material (mask) layers, and finally directing a high pressure gas
or liquid through the mask openings to form holes in the moldable
material, then solidifying and demolding the moldable material,
which will exhibit an array of hollow microstructures.
[0008] Accordingly, it is another advantage of the present
invention to provide a methodology for forming a microstructure
having an array of microelements with openings, in which the
microstructure is formed by first depositing a material on a
tooling (such as a die or mold) of a predetermined shape up to a
predetermined thickness, in which the tooling exhibits a plurality
of protrusions that cause openings to be created in the first
material, then releasing the material and placing a second material
thereupon which acts as a mask over the first material, the mask
having openings at predetermined locations, in which the mask
includes protrusions that are directed toward openings formed in
the first material, then placing a moldable (third) material
against a surface formed by both of the first material and second
material (mask) layers, and finally directing a high pressure gas
or liquid through the mask openings to form holes in the moldable
material, then solidifying and demolding the moldable material,
which will exhibit an array of hollow microstructures that protrude
from a substrate, and in which the hollow microelements exhibit an
enlarged inner opening (or diameter) near the tips of the
individual microelements.
[0009] It is yet another advantage of the present invention to
provide a methodology for forming a microstructure having an array
of microelements with openings, in which the microstructure is
formed by first depositing a material on a tooling (such as a die
or mold) of a predetermined shape up to a predetermined thickness,
in which the tooling exhibits a plurality of protrusions that cause
openings to be created in the first material, in which the first
deposited material is formed at a first thickness which creates
openings of a first interior dimension, and a second material is
deposited on a tooling up to a second, greater thickness (if the
tooling is of the same size and shape), or at least to a thickness
that creates openings of a second interior dimension that is
smaller than the first interior dimension, after which the first
and second materials are released from their toolings then stacked
together such that their respective openings are aligned, after
which a moldable (third) material is placed against a surface
formed by both of the first material and second material layers,
and finally directing a high pressure gas or liquid through the
openings of the second material, thereby forming holes in the
moldable material of a size controlled by the second interior
dimension, then solidifying and demolding the moldable material,
which will exhibit an array of hollow microstructures.
[0010] It is still another advantage of the present invention to
provide a methodology for forming a microstructure having an array
of microelements with openings, in which the microstructure is
formed by first depositing a material on a tooling (such as a die
or mold) of a predetermined shape up to a predetermined thickness,
in which the tooling exhibits a plurality of protrusions that cause
openings to be created in the first material, in which the first
material is deposited in a sufficient thickness to create rather
small openings in the first material, then releasing the first
material and placing a moldable (second) material against a surface
formed by the first material and directing a high pressure gas or
liquid through the rather small openings to form holes in the
moldable material, then solidifying and demolding the moldable
material, which will exhibit an array of hollow
microstructures.
[0011] Additional advantages and other novel features of the
invention will be set forth in part in the description that follows
and in part will become apparent to those skilled in the art upon
examination of the following or may be learned with the practice of
the invention.
[0012] To achieve the foregoing and other advantages, and in
accordance with one aspect of the present invention, a method for
constructing a microstructure is provided, in which the method
comprises the following steps: (a) providing a moldable material to
be formed into a predetermined shape; (b) during a molding
procedure, forcing a predetermined fluid under pressure toward a
surface of the moldable material, the predetermined fluid forming
at least one opening at the surface; and (c) substantially
solidifying the moldable material while the pressurized
predetermined fluid continues to flow toward the surface, thereby
forming a solid microstructure which includes the at least one
opening at the surface.
[0013] In accordance with another aspect of the present invention,
a method for constructing a microstructure is provided, in which
the method comprises the following steps: (a) providing a tooling
structure having a first surface and a second surface opposite the
first surface, and having a substrate having a plurality of
protrusions formed upon the first surface, the plurality of
protrusions exhibiting at least one height; (b) depositing a
material upon the first surface of the tooling structure, the
material having a thickness that is generally less than the at
least one height of the plurality of protrusions; and (c)
separating the material from the tooling structure to form a
micromold, the micromold exhibiting a first plurality of openings
that correspond to a portion of a three-dimensional negative form
of the plurality of protrusions of the tooling structure along the
thickness of the material.
[0014] In accordance with yet another aspect of the present
invention, a method for constructing a microstructure is provided,
in which the method comprises the following steps: (a) providing a
tooling structure having a first surface and a second surface
opposite the first surface, and having a first substrate having a
plurality of protrusions formed upon the first surface, the
plurality of protrusions exhibiting at least one height; (b)
depositing a first material upon the first surface of the tooling
structure, the first material having a thickness that is generally
less than the at least one height of the plurality of protrusions;
(c) releasing the first material from the tooling structure, the
first material exhibiting a plurality of openings that correspond
to a portion of a three-dimensional negative form of the plurality
of protrusions of the tooling structure along the thickness of the
first material, the plurality of openings exhibiting at least one
predetermined inner area proximal to a third surface of the first
material; (d) providing a backing member at a predetermined and
spaced-apart distance from a fourth surface of the first material,
the fourth surface being opposite the third surface of the first
material, the backing member exhibiting comparatively little
porosity with respect to a moldable second material, but exhibiting
substantial porosity with respect to a predetermined fluid; (e)
introducing the moldable second material between the backing member
and the fourth surface of the first material, and forcing the
predetermined fluid under pressure through the plurality of
openings of the first material to form at least one channel in the
second material between the first material and the backing member,
and substantially solidifying the second material while the
pressurized predetermined fluid continues to flow through the
plurality of openings; and (f) separating the solidified second
material from the backing member and the first material, the
solidified second material exhibiting a second substrate and
exhibiting a plurality of microelements that substantially
correspond in size and shape to a three-dimensional negative form
of the plurality of openings in the first material, and further
exhibiting the at least one channel running completely through the
second substrate and at least one of the plurality of
microelements.
[0015] Still other advantages of the present invention will become
apparent to those skilled in this art from the following
description and drawings wherein there is described and shown a
preferred embodiment of this invention in one of the best modes
contemplated for carrying out the invention. As will be realized,
the invention is capable of other different embodiments, and its
several details are capable of modification in various, obvious
aspects all without departing from the invention. Accordingly, the
drawings and descriptions will be regarded as illustrative in
nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings incorporated in and forming a part
of the specification illustrate several aspects of the present
invention, and together with the description and claims serve to
explain the principles of the invention. In the drawings:
[0017] FIGS. 1-6 illustrate various steps in a process for creating
an array of microelements on a microstructure, in which a material
is deposited on a pre-shaped tooling, and then released from that
tooling and covered with a mask having a plurality of openings,
after which a layer of moldable material is placed against the
surface of the combination, and pressurized gas or liquid is
directed to create openings through the moldable material at
locations where the formed microelements project from a substrate.
All of these views are elevational cross-section views.
[0018] FIGS. 7-12 illustrate various steps in a process for
creating an array of microelements on a microstructure, in which a
material is deposited on a pre-shaped tooling, and then released
from that tooling and covered with a mask having a plurality of
openings, in which the mask exhibits a short hollow protrusion near
the opening therein, after which a layer of moldable material is
placed against the surface of the combination, and pressurized gas
or liquid is directed to create openings through the moldable
material at locations where the formed microelements project from a
substrate. All of these views are elevational cross-section
views.
[0019] FIGS. 13-20 illustrate various steps in a process for
creating an array of microelements on a microstructure, in which a
first material is deposited on a pre-shaped tooling up to a first
predetermined depth, and a second material is deposited on a
pre-shaped tooling up to a second different depth, and after the
two materials are released from their respective toolings, they are
abutted against one another such that their openings are well
aligned. After that has occurred, a moldable (third) material is
placed against the surface of the first material, while high
pressure gas or liquid is directed through openings in the second
material, thereby forming through-holes in the moldable material,
and when this moldable material is solidified and released, it
exhibits hollow microelements that protrude from a substrate. All
of these views are elevational cross-section views.
[0020] FIGS. 21-24 illustrate various steps in a process for
creating an array of microelements on a microstructure, in which a
first material is deposited on a pre-shaped tooling up to a
predetermined thickness, and once the material is released, it will
become a mold shape having a plurality of small openings. A
moldable (second) material is then placed against this released,
deposited material, and pressurized gas or liquid is directed
through the openings in the first material, thereby forming
through-holes in the moldable material. When the moldable material
is solidified and released, it exhibits a plurality of hollow
microelements that protrude from a substrate. All of these views
are elevational cross-section views.
[0021] FIGS. 25-26 illustrate the final steps of an alternative
process creating an array of microelements on a microstructure, in
which the deposited material of FIG. 22 is used to create a
microstructure having openings that do not extend entirely through
the moldable material.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Reference will now be made in detail to the present
preferred embodiment of the invention, an example of which is
illustrated in the accompanying drawings, wherein like numerals
indicate the same elements throughout the views.
[0023] As described below, the present invention includes several
different methodologies for manufacturing hollow microneedles (or
"microelements"), in which such microneedles can be of various
lengths. The microneedles can be, for example, as long as 2000
microns or 3000 microns, or as short as, for example, one-tenth of
a micron. (A micron is a micrometer, which is 10.sup.-6 meters.)
The lengths of the microelements can be substantially constant over
the entire array if desired, or the lengths can vary over the array
for a particular application. The maximum desired length will
typically depend upon the particular application to which the
microstructure will be used, and for example, it may be desirable
to limit the length so that the microelements will not completely
penetrate the stratum corneum layer of animal (e.g., human)
skin.
[0024] It should be noted that some applications for
microstructures does not involve penetrating the skin at all. For
example, an exfoliation application would tend to remove substances
from the outer skin, perhaps including hair. At the same time, a
fluidic compound could be applied to the skin.
[0025] The shapes of the microneedles can be made using various
materials, even including metal if desired. The final array
structure that contains multiple microneedles/microelements is
generally referred to herein as a "microstructure."
[0026] Referring now to FIG. 1, a pre-shaped tooling is prepared in
a manner that one might prepare a mold or die for a plastic molding
or a metal die-casting procedure. The tooling is generally
designated by the reference numeral 10, and exhibits a substrate 12
which has a pair of pyramidal shaped protrusions 14 that end in an
uppermost peak 18. (It will be understood that this tooling 10 will
actually contain hundreds, if not thousands, of such protrusions
14.) The upper planar surface between the protrusions 14 are
indicated at the reference numeral 16. The tooling 10 could be
machined or etched in such a manner so that the final shape of the
projections (protrusions) 14 will represent a desired shape or
shapes of microstructures to be formed, in which these shapes could
be of any manner desired by a system designer, such as pyramids,
cones, cylinders, and/or wedges. Of course, combinations of shapes
could be made or formed as protrusions on the same substrate 12.
The material of the tooling could be metallic, ceramic, or silicon,
or perhaps some other type of material, as desired by the system
designer.
[0027] Referring now to FIG. 2, a second material 22 is deposited
on the tooling 10 using a process such as electroplating, spin
coating, or vapor deposition. The overall resulting structure is
generally designated by the reference numeral 20, and the second
material 22 is formed so as to exhibit a predetermined thickness
above the planar surfaces 16, in which the predetermined thickness
is illustrated at the reference arrow 24.
[0028] The second material 22 forms a partial negative micromold
from the original tooling 10, and its height will be controlled to
a predetermined value by any number of methodologies that are known
in the art. This step could even be accomplished by using a plastic
injection molding procedure, which would require a second mold half
to mate against the upper surface of the material 22 and the upper
surfaces of the projections 14. However, such a molding (or even
casting) procedure is not specifically required for the present
invention, although easily accomplished within the principles of
the present invention.
[0029] Referring now to FIG. 3, the deposited second material 22
has been separated or detached from the tooling, and now is
generally designated by the reference numeral 30. Once detached,
this layer of second material 22 will be substantially planar on
both its top and bottom surfaces, and will also exhibit openings
therethrough, as indicated at the reference arrows 32. These
openings 32 will have a shape that is determined by the shape of
the protrusions 14 of the original tooling 10, i.e., a
three-dimensional negative shape or "form."
[0030] Referring now to FIG. 4, a mask layer is placed on the upper
surface of the material 22, in which this mask is substantially
planar and exhibits openings. The overall combination is generally
designated by the reference numeral 40. The mask itself is
designated by the reference numeral 42, and its openings by the
reference arrows 44. At least some of the openings 44 are to be
substantially aligned with some of the openings 32 of the material
22, such that the circumference (if circular) of the openings 44
will align within the area or perimeter of the circumference (if
circular) of the openings 32. Since these structures are to be
relatively small in overall size (and therefore referred to as
"microstructures"), the inner perimeters or areas of openings 32
and 44 should be substantially "well-aligned."
[0031] Referring now to FIG. 5, the structure 40 is now used in a
molding procedure in which a bottom mold-half (or "backing plate")
52 is provided, and moldable material is placed between this
backing half and the upper structure 40. This overall combination
is generally designated by the reference numeral 50. After the
structure 40 is positioned in a predetermined spaced-apart location
with respect to the backing plate 52, a moldable material 54 is
interjected or introduced therebetween, which fills up the
substantially planar area between the material (micromold) 22 and
the backing plate 52, as well as filling the volumetric spaces 56.
Before the moldable material 54 hardens, a pressurized fluid (e.g.,
a high pressure gas or liquid) is directed through the openings 44
at locations generally designated by the reference numeral 58 on
FIG. 5.
[0032] This high pressure gas or liquid will pass through the
openings 44 and down through the backing plate 52, which could be
manufactured of a substantially porous media with respect to the
high pressure gas or liquid. Of course, in this arrangement the
backing plate 52 cannot be substantially porous with respect to the
moldable material 54 itself. That is, backing plate 52 should
exhibit comparatively little porosity characteristics with regard
to the flowability of moldable material 54 having a capability to
leak therethrough perhaps some leakage would be permissible, but it
would likely complicate the manufacturing process.
[0033] In some processes, it may be best if the backing plate 52
allows the pressurized gas or liquid to flow therethrough without
causing a significant backpressure, which otherwise would of course
add to the power requirements for the process of manufacturing, as
well as needing a larger capacity pump, or fan ("blower") and motor
combination. However, this is not a strict requirement--a
substantially solid (non-porous) backing plate (with respect to the
pressurized gas/liquid) might have other advantages, and still
nevertheless be used in the present invention along with the
appropriate pressure source for the fluid to be directed through
the openings 44. If there is no need to maintain a fairly precise
constant inner diameter of the through-holes 58 that will be formed
in the moldable material 54, then certainly a non-porous backing
plate 52 could be used in an alternative arrangement. In this
alternative arrangement, the bottom-most portions (in the views) of
the through-holes 58 may exhibit a smaller open (inner) area than
at the top-most (in the views) portions of the same through-holes;
however, if the bottom-most openings are sufficiently large to
allow a predetermined molecule size (of a fluid) to pass
therethrough, then such an arrangement will be sufficient.
[0034] As the moldable material 54 fills all of the space between
material (micromold) 22 and backing plate 52, including the shaped
volumes at 56, and while the high pressure gas or liquid is blown
through the openings at 58 thus forming channels therethrough, the
entire structure 50 is somewhat cooled so that the moldable
material will harden. Once the moldable material 54 solidifies, it
will be released from the "mold halves" 22 and 52, thereby
exhibiting a shape illustrated in FIG. 6, generally designated by
the reference numeral 60. The moldable material now exhibits a
substrate 54 and multiple microelements 56 that project or protrude
from the substrate 54. Each of the microelements 56 exhibits a
hollow through-hole 58. These microelements 56 are designed so as
to penetrate the outer layers of animal skin (e.g., through the
stratum corneum of human skin), and the openings or through-holes
58 will allow for a fluid to be dispensed through the skin barrier
or membrane barrier of the tissue that has been penetrated by the
microelements 56. As noted above, the microelements 56 can be made
to any desired shape, including hollow cylinders, or individual
pyramidal shapes with through-holes. The actual material used to
form the microstructure 60 would typically be a moldable plastic or
polymer, although other materials could be utilized, even perhaps
some type of metal in a casting process (although the pressurized
gas or liquid that would form the through-holes in metal would
indeed require a very high pressure to be applied, or for a
chemical reaction to additionally be created during the forming and
cooling stages of the process).
[0035] As noted above, the fluid itself can consist of a gas or
liquid, such as a high pressure liquid or a hot gas that forms
streams (e.g., fluid streams) through the openings 44, and which
are used to mechanically force openings 58 through the moldable
material while it is still in a mainly fluidic state (i.e., before
solidifying). The pressurized fluid could comprise a heated gas,
such as steam, or perhaps a heated liquid or a liquid solvent. As
an alternative, a gas or liquid (fluidic) stream that tends to
chemically dissolve the moldable material 54 could be used,
including a situation where the "moldable" material 54 turns out to
consist of a metal.
[0036] When viewing FIG. 4, it can be seen that the mask plate 42
has portions that in essence "overhang" the tops of the openings 32
of the bottom layer (i.e., micromold) 22, in the structure 40. This
"overhang" allows a reusable mask plate 42 to provide smaller
openings 44 that will define the wall thickness and inner perimeter
(and inner area) of the hollow microstructures that are formed by
the time the process reaches FIG. 6. In other words, the inner
dimensions of the channels 58 are substantially dependent on the
interior perimeter (e.g., the inner diameter, if circular) of the
openings 44 in the mask plate 42, and not on the interior perimeter
(e.g., the inner diameter, if circular) of the openings 32 in the
structure 30 of FIG. 3.
[0037] It will be understood that the shapes and angles depicted
for the openings 32 and 44 are for purposes of illustration and
explanation, and that various other shapes and angles could be used
without departing from the principles of the present invention.
Moreover, the ratio of the inner dimensions of these openings 32
and 44 are also for purposes of illustration and explanation, and
that various other ratios could be used without departing from the
principles of the present invention. Certainly, virtually any
microstructure dimensions could be used for the tooling protrusion
14 sizes, the thickness 24 of the material 22, and the thickness of
the substrate 54 and length of the microelements 56 of the final
microstructure 60, and are thus within the contemplation of the
inventors.
[0038] A second embodiment that illustrates a procedure for forming
microstructures with multiple microelements is illustrated in FIGS.
7-12, and will now be discussed in detail. Referring now to FIG. 7,
a pre-shaped tooling is prepared in a manner that one might prepare
a mold or die for a plastic molding or a metal die-casting
procedure. The tooling is generally designated by the reference
numeral 110, and exhibits a substrate 112 which has a pair of
pyramidal shaped protrusions 114 that end in an uppermost peak 118.
(It will be understood that this tooling 110 will actually contain
hundreds, if not thousands, of such protrusions 114.) The upper
planar surface between the protrusions 114 are indicated at the
reference numeral 116. The tooling 110 could be machined or etched
in such a manner so that the final shape of the projections
(protrusions) 114 will represent a desired shape or shapes of
microstructures to be formed, in which these shapes could be of any
manner desired by a system designer, such as pyramids, cones,
cylinders, and/or wedges. Of course, combinations of shapes could
be made or formed as protrusions on the same substrate 112. The
material of the tooling could be metallic, ceramic, or silicon, or
perhaps some other type of material, as desired by the system
designer.
[0039] Referring now to FIG. 8 a second material 122 is deposited
on the tooling 110 using a process such as electroplating, spin
coating, or vapor deposition. The overall resulting structure is
generally designated by the reference numeral 120, and the second
material 122 is formed so as to exhibit a predetermined thickness
above the planar surfaces 116, in which the predetermined thickness
is illustrated at the reference arrow 124.
[0040] The second material 122 forms a partial negative micromold
from the original tooling 110, and its height will be controlled to
a predetermined value by any number of methodologies that are known
in the art. This step could even be accomplished by using a plastic
injection molding procedure, which would require a second mold half
to mate against the upper surface of the material (micromold) 122
and the upper surfaces of the projections 114. However, such a
molding (or even casting) procedure is not specifically required
for the present invention, although easily accomplished within the
principles of the present invention.
[0041] Referring now to FIG. 9, the deposited second material 122
has been separated or detached from the tooling, and now is
generally designated by the reference numeral 130. Once detached,
this layer of second material 122 will be substantially planar on
both its top and bottom surfaces, and will also exhibit openings
therethrough, as indicated at the reference arrows 132. These
openings 132 will have a shape that is determined by the shape of
the protrusions 114 of the original tooling 110, i.e., a
three-dimensional negative shape or "form."
[0042] Referring now to FIG. 10, a mask layer is placed on the
upper surface of the material 122, in which this mask is
substantially planar and exhibits openings. The overall combination
is generally designated by the reference numeral 140. The mask
itself is designated by the reference numeral 142, and its openings
by the reference arrows 144. At least some of the openings 144 are
to be substantially aligned with some of the openings 132 of the
material 122, such that the circumference (if circular) or area of
the openings 144 will align within the perimeter of the
circumference (if circular) or area of the openings 132. Since
these structures are to be relatively small in overall size (and
therefore referred to as "microstructures"), the inner
perimeters/areas of openings 132 and 144 should be substantially
"well-aligned."
[0043] The mask plate 142 has a somewhat different shape than the
earlier mask plate 42, which was discussed above in reference to
FIG. 4. In FIG. 10, it can be seen that the mask plate 142 not only
exhibits openings at 144, but also exhibits a perpendicular
structure that protrudes in a downward direction (as seen in FIG.
10), forming a hollow protrusion into the volume occupied by the
opening 132 in the layer of material 122. This protrusion 146 will
ultimately create the shape of the microelements that will be
formed from this structure 140, and that shape will be somewhat
different than illustrated in FIG. 6.
[0044] Referring now to FIG. 11, the structure 140 is now used in a
molding procedure in which a bottom mold-half (or "backing plate")
152 is provided, and moldable material is placed between this
backing half and the upper structure 140. This overall combination
is generally designated by the reference numeral 150. After the
structure 140 is positioned in a predetermined spaced-apart
location with respect to the backing plate 152, a moldable material
154 is interjected or introduced therebetween, which fills up the
substantially planar area between the material 122 and the backing
plate 152, as well as filling the volumetric spaces 156. Before the
moldable material 154 hardens, a pressurized fluid (e.g., a high
pressure gas or liquid) is directed through the openings 144 at
locations generally designated by the reference numeral 158 on FIG.
11. This high pressure gas or liquid will pass through the openings
144 and down through the backing plate 152, which could be
manufactured of a substantially porous media with respect to the
high pressure gas or liquid. Of course, the backing plate 152
cannot be substantially porous with respect to the moldable
material 154 itself. Alternatively, the backing plate 152 could
have a non-porous characteristic with respect to the pressurized
gas/liquid, along with an appropriate pressure source.
[0045] As the moldable material 154 fills all of the space between
material 122 and backing plate 152, including the shaped volumes at
156, and while the high pressure gas or liquid is blown through the
openings at 158 thus forming channels therethrough, the entire
structure 150 is somewhat cooled so that the moldable material will
harden. Once the moldable material 154 solidifies, it will be
released from the "mold halves" 122 and 152, thereby exhibiting a
shape illustrated in FIG. 12, generally designated by the reference
numeral 160. The moldable material now exhibits a substrate 154 and
multiple microelements 156 that project or protrude from the
substrate 154. Each of the microelements 156 exhibits a hollow
through-hole 158. These microelements 156 are designed so as to
penetrate the outer layers of animal skin (e.g., through the
stratum corneum of human skin), and the openings or through-holes
158 will allow for a fluid to be dispensed through the skin barrier
or membrane barrier of the tissue that has been penetrated by the
microelements 156.
[0046] As noted above, the microelements 156 can be made to any
desired shape, including hollow cylinders, or individual pyramidal
shapes with through-holes. The actual material used to form the
microstructure 160 would typically be a moldable plastic or
polymer, although other materials could be utilized, even perhaps
some type of metal in a casting process (although the pressurized
gas or liquid that would form the through-holes in metal would
indeed require a very high pressure to be applied, or a chemical
reaction to additionally be created, during the forming and cooling
stages of the process).
[0047] The shape of the openings of the individual microelements
156 is somewhat different than depicted at 56 in FIG. 6, in that
the opening at 162 is larger in its inner dimension, as illustrated
at 162 on FIG. 12. In other words, the interior perimeter or area
of the portion of the through-hole at 158 is smaller than the
interior perimeter or area of the portion of the through-hole at
162, which also provides for sharper edges at the uppermost tips of
the microelements 156.
[0048] When viewing FIG. 10, it can be seen that the mask plate 142
has portions that in essence "overhang" the tops of the openings
132 of the bottom layer 122, in the structure 140. This "overhang"
allows a reusable mask plate 142 to provide smaller openings 144
and protrusions 146 that will define the wall thicknesses and inner
perimeters (and inner areas) of the hollow microstructures that are
formed by the time the process reaches FIG. 12. In other words, the
inner dimensions of the channels 158 and 162 are substantially
dependent on the interior perimeters (e.g., the inner diameters, if
circular) of the openings 144 and protrusions 146 in the mask plate
142, and not on the interior perimeters (e.g., the inner diameters,
if circular) of the openings 132 in the structure 130 of FIG.
9.
[0049] It will be understood that the shapes and angles depicted
for the openings 132 and 144 are for purposes of illustration and
explanation, and that various other shapes and angles could be used
without departing from the principles of the present invention.
Moreover, the ratio of the inner dimensions of these openings 132
and 144 are also for purposes of illustration and explanation, and
that various other ratios could be used without departing from the
principles of the present invention. Certainly, virtually any
microstructure dimensions could be used for the tooling protrusion
114 sizes, the thickness 124 of the material 122, the protrusions
146 of the mask, and the thickness of the substrate 154 and length
of the microelements 156 of the final microstructure 160, and are
thus within the contemplation of the inventors.
[0050] A third embodiment that illustrates a procedure for forming
microstructures with multiple microelements is illustrated in FIGS.
13-20, and will now be discussed in detail. Referring now to FIG.
13, a tooling structure generally designated by the reference
numeral 210 is provided having a predetermined shape for its upper
surface, in which its substrate 212 has a relatively planar upper
surface at 216 along with projections 214 that have uppermost peaks
at 218.
[0051] Referring now to FIG. 14, a second material 222 is deposited
on the tooling 210 using a process such as electroplating, spin
coating, or vapor deposition. The overall resulting structure is
generally designated by the reference numeral 220, and the second
material 222 is formed so as to exhibit a predetermined thickness
above the planar surfaces 216, in which the predetermined thickness
is illustrated at the reference arrow 224.
[0052] The second material 222 forms a partial negative mold from
the original tooling 210, and its height will be controlled to a
predetermined value by any number of methodologies that are known
in the art. This step could even be accomplished by using a plastic
injection molding procedure, which would require a second mold half
to mate against the upper surface of the material 222 and the upper
surfaces of the projections 214. However, such a molding (or even
casting) procedure is not specifically required for the present
invention, although easily accomplished within the principles of
the present invention.
[0053] Referring now to FIG. 15, the deposited second material 222
has been separated or detached from the tooling, and now is
generally designated by the reference numeral 230. Once detached,
this layer of second material 222 will be substantially planar on
both its top and bottom surfaces, and will also exhibit openings
therethrough, as indicated at the reference arrows 232. These
openings 232 will have a shape that is determined by the shape of
the protrusions 214 of the original tooling 210, i.e., a
three-dimensional negative shape or "form."
[0054] The same type of tooling 212 (i.e., in size and shape) can
also be used again in which a layer of material 244 is deposited to
a greater thickness, as illustrated in FIG. 16, in which this
structure is generally designated by the reference numeral 240. The
tooling has a bottom structure 242 having multiple protrusions,
with peaks at 248. The deposited material 244 is allowed to acquire
a thickness so that its uppermost dimension is illustrated at 246,
and approaches the height of the peaks 248. When this deposited
layer of material 244 is detached from the tooling 242, it will
exhibit fairly small openings at 252, as illustrated in FIG. 17.
This deposited material 244 is generally designated by the
reference numeral 250 on FIG. 17, and will both be thicker than the
material 222 of FIG. 15, and will exhibit smaller openings at 252
as compared to the openings 232 of FIG. 15.
[0055] As an obvious alternative, the tooling 242 could exhibit a
somewhat different size and/or shape from that of tooling 212, such
that the height 246 of the deposited material 244 (above the planar
surface 247) could be precisely the same as the height 224 (above
the planar surface 216) of the deposited material 222. In that
circumstance, it would still be desirable for the openings 252 to
be the controlling dimension for the later process steps discussed
below in reference to FIGS. 18-20 (i.e., openings 252 should be
smaller in their interior perimeters or inner areas than openings
232). This could be simply accomplished by providing a different
shape and/or size to the projections 249, having their peaks at
248.
[0056] These structures 230 and 250 are now abutted against one
another as illustrated in FIG. 18, thereby producing a structure
generally designated by the reference numeral 260. The bottom
structure 230 includes the larger openings 232, while the upper
structure 250 exhibits the thicker layer of material 244 with the
openings 252 that narrow or taper down to a smaller interior
perimeter/area, as seen at the reference arrow 262. The
perimeter/area of openings at 262 should generally be aligned
within the perimeter/area of openings 232, and thus these
structures 230 and 250 should be substantially well-aligned. These
two layers 230 and 250 are not necessarily to be permanently
attached or affixed to one another, however, they are to be held
firmly in place during the next step of the procedure, which is
illustrated in FIG. 19.
[0057] In FIG. 19, a bottom mold-half or backing plate 272 is
brought to a predetermined spaced-apart position from the structure
260, and a moldable material 274 is interjected or introduced
therebetween. This overall structure is illustrated in FIG. 19, and
generally designated by the reference numeral 270. While the
backing plate 272 is in position, the moldable material 274 is
introduced (perhaps by an injection molding process) such that it
fills the volume between the layer 222 and the backing plate 272,
as well as the volume at 276 that was formed by the opening 232 in
the layer 230. While this introduction of moldable material is
proceeding, a high pressure fluid (i.e., a gas or liquid) is
directed through the openings 252 and down through the openings 232
(which is seen as subsisting of moldable material 276), thereby
forming channels 278 in the moldable material. This high pressure
gas or liquid thereby forms the hollow channels 278, while passing
through the backing plate 272, which could be composed of a porous
media with respect to the gas or liquid streams. Of course, the
backing plate 272 is not substantially porous with respect to the
moldable material 274. As noted above, a backing plate such as
plate 272 need not necessarily be porous with respect to the
pressurized gas/liquid, when used with an appropriate pressure
source for the pressurized fluid.
[0058] The high-pressure fluid continues to flow while the moldable
material is cooled until it solidifies, such that the channels 278
will become permanent. After the moldable material 274 has
solidified, it will be released from the mold halves formed by the
elements 260 and 272, thereby providing the "final" structure
generally designated by the reference numeral 280, illustrated in
FIG. 20. As can be seen in FIG. 20, the microstructure 280 includes
a substrate 274 and multiple microelements 276, which have
through-holes or openings at 278. In a similar manner to the
procedures and structures discussed above with respect to FIGS.
1-12, the microelements 276 can be of virtually any size and shape
chosen by a system designer, including conical, pyramidal,
cylindrical, or even wedged shapes. Moreover, a combination of such
shapes can be used upon a single substrate 274 to form a single
microstructure 280 with microelements of multiple shapes, or in
multiple patterns of arrays.
[0059] It will be understood that the smaller openings 252 of the
layer 244 essentially act as a "mask," such that they "overhang"
the larger openings 232 in the layer 222, as seen in FIG. 18. These
smaller openings at the narrowest portions of the openings 252 are
indicated at the reference arrows 262, and it is the interior
perimeter at these narrow-most (or tapered) openings 262 that will
define the wall thickness and inner dimensions (e.g., open areas)
of the microelements 276 and the through-holes 278.
[0060] It will be understood that the shapes and angles depicted
for the openings 232 and 252 are for purposes of illustration and
explanation, and that various other shapes and angles could be used
without departing from the principles of the present invention.
Moreover, the ratio of the inner dimensions of these openings 232
and 252 are also for purposes of illustration and explanation, and
that various other ratios could be used without departing from the
principles of the present invention. Certainly, virtually any
microstructure dimensions could be used for the tooling protrusion
214 sizes, the thicknesses 224 and 246 of the materials 222 and
246, and the thickness of the substrate 274 and length of the
microelements 276 of the final microstructure 280, and are thus
within the contemplation of the inventors.
[0061] A fourth embodiment that illustrates a procedure for forming
microstructures with multiple microelements is illustrated in FIGS.
21-24, and will now be discussed in detail. Referring now to FIG.
21, a tooling 312 is provided with planar surfaces 316 and multiple
protrusions or projections 314 having peaks at 318. A second
material 322 is deposited on this tooling, thereby producing the
structure generally designated by the reference numeral 310 in FIG.
21. As it is being deposited, the second material 322 is allowed to
come up to a predetermined thickness, such that its height at the
reference arrow 324 is almost the same as the height of the peaks
318 of the tooling 312. When the deposited material 322 is
separated from the tooling 312, it produces a structure generally
designated by the reference numeral 320, as illustrated in FIG. 22.
The openings 326 that have been formed in the material 322 taper
down to their narrowest points at the reference arrows 328. These
tapered openings 328 can be controlled merely by controlling the
amount of material, or the height of the material, that defines the
dimension 324 in FIG. 21. If desired, the process to form the
structure 310 in FIG. 21 could involve a plastic injection molding
procedure, rather than some type of depositing procedure. In
addition, a die-casting methodology could be used, if it is desired
for the material used for the structure 320 to comprise metal,
rather than a moldable plastic or polymer material. If either
injection molding or die-casting is to be used, then a top
"mold-half" or "die-half" will also be needed.
[0062] Referring now to FIG. 23, the structural layer 322 is
brought within a predetermined spaced-apart distance to a second
mold-half or backing plate 332, and a moldable material is
interjected therebetween, thus forming the structure generally
designated by the reference numeral 330. The moldable material at
334 will fill the space between the top surface of the backing
plate 332 and the bottom surfaces of the tooling 322, including the
openings 326, which are filled by the moldable material at 336.
While the moldable material is introduced, a high pressure gas or
liquid is directed from above, and will pass through the relatively
small openings 328 in the tooling 322, thereby forming channels 338
in the moldable material. This situation is maintained until the
moldable material has completely filled the appropriate volume, and
is then cooled so that it will solidify. Once the moldable material
334 has become a solid, the "mold halves" 322 and 332 will separate
such that a structure 340 is released, as illustrated in FIG. 24.
This microstructure 340 will include a substrate 334 that exhibits
multiple microelements 336 which protrude or project above the
upper planar surface, and in which these microelements 336 have
through-openings at 338.
[0063] As can be seen from the above description, this embodiment
of FIGS. 21-24 does not require a separate mask plate to help
define the size and shape of the openings that are formed through
the microelements 336. This not only eliminates a part or fixture
while stepping through the inventive methodology in forming these
microstructures, but also eliminates the requirement of aligning
any type of mask plate with the earlier-formed tooling structure
that is used to shape the microelements themselves. All that is
required in this embodiment of FIGS. 21-24 is that the height of
the initial material 322 (see FIG. 21) be properly controlled so
that the size of the openings formed by the microelement
projections 314 are of the correct non-circular perimeter (or
correct diameter, if circular) or area when openings are formed at
their narrowest extents, as at 328 (as seen in FIG. 22).
[0064] It will be understood that the shapes and angles depicted
for the openings 328 are for purposes of illustration and
explanation, and that various other shapes and angles could be used
without departing from the principles of the present invention.
Certainly, virtually any microstructure dimensions could be used
for the tooling protrusion 314 sizes, the thickness 324 of the
material 322, and the thickness of the substrate 334 and length of
the microelements 336 of the final microstructure 340, and are thus
within the contemplation of the inventors.
[0065] For all embodiments of the present invention, it will be
understood that the high pressure gas or liquid that forms the
through-holes in the moldable material can be of a continuous
pressure, or can be of a pulsed pressure. Also, the high pressure
fluid (gas or liquid) could instead be controlled for its time
duration so as to create indentations, rather than through-holes
(as discussed below in greater detail). In addition, the
interjection of the moldable material can be accomplished by
injection molding, or perhaps by embossing a film of moldable
material, or even by casting, if desired. It will also be
understood that the physical orientation of the mechanical elements
in the illustrations of FIGS. 5, 11, 19, and 23 could be different
from that illustrated, and in fact it could be oriented
upside-down, or even at 90.degree. or other angles, if desired.
[0066] The tooling of FIG. 21 is used to create a microstructure
shape 320 that is illustrated in FIG. 22, as discussed above.
However, as noted above, it is not necessary to always create
openings or holes that extend entirely through the final
microstructure. An example of constructing such a structure is
illustrated in FIGS. 25 and 26. In FIG. 25, the deposited material
322 is again used as a mold shape or mold-half, while a backing
plate 352 provides the "bottom" mold shape (as seen in this view).
Moldable material 354 is interposed between these mold shapes 322
and 352, thus creating the temporary structure generally designated
by the reference numeral 350. In this particular process, it is not
at all necessary or desired for the backing plate 352 to have any
type of porous characteristics with respect to a pressurized
fluid.
[0067] The moldable material at 354 will fill the space between the
top surface of the backing plate 352 and the bottom surfaces of the
tooling 322, including the openings 326, which are filled by the
moldable material at 356. While the moldable material is
introduced, a high pressure gas or liquid is directed from above,
and will pass through the relatively small openings 328 in the
tooling 322, thereby forming channels 360 in the moldable material.
This situation is maintained until the moldable material has
completely filled the appropriate volume, and is then cooled so
that it will solidify. Once the moldable material 354 has become a
solid, the "mold halves" 322 and 352 will separate such that a
structure 370 is released, as illustrated in FIG. 26. This
microstructure 340 will include a substrate 354 that exhibits
multiple microelements 356 which protrude or project above the
upper planar surface, and in which these microelements 356 have
openings at 360.
[0068] In this alternative process, when the pressurized fluid is
directed through the openings in the material 322, it is done in a
manner such that the openings or channels 360 created in the shaped
volume 356 will not extend completely through to the backing plate
352. A final microstructure 370 is provided, in which the openings
or indentations 360 do not run completely through to the bottom
surface of the substrate 354, and a portion (at 362) of solid
material remains at the bottom-most extent of the openings 360.
This can be accomplished by controlling the fluidic pressure and
the time duration for sending the pressurized fluid through the
openings 328, such that the moldable material is solidified before
the openings/indentations 360 can form a complete channel through
to the bottom of the substrate 354. The use of a pulsed pressure
source could aid in constructing this microstructure. Such
indentations (instead of through-holes) could be formed in
conjunction with any of the embodiments disclosed herein.
[0069] It will be understood that the exact shapes of the
projections of the tooling can vary from those illustrated in the
figures, without departing from the principles of the present
invention. Examples of possible shapes are disclosed in the patent
documents noted above in the BACKGROUND, also assigned to The
Procter & Gamble Company, which are incorporated by reference
herein. It will also be understood that the relative ratios of
openings for various hole or channel sizes can vary from those
illustrated, without departing from the principles of the present
invention. It will be further understood that the materials
discussed above are merely examples, and virtually any type of
moldable or castable material could be used in conjunction with the
principles of the present invention to manufacture the
microstructures using the methodologies described.
[0070] It will be further understood that the methodologies of the
present invention extend to a process for making through-holes or
indentations in a microstructure, whether or not these
through-holes/indentations are physically located within a
protrusion of that microstructure. In other words, such
through-holes/indentations could be located along a portion of the
microstructure's substrate that is otherwise substantially planar
along its top and bottom surfaces. This is easily accomplished, for
example, by creating some openings 44 in the mask plate 42 (see
FIG. 4) that do not line up with openings 32 (see FIG. 3) in the
tooling 30. In that situation, the pressurized fluid that is
directed through the openings 44 would create some openings (not
shown in FIG. 5) that extend through only the substrate 54 of the
moldable material, and not through one of the protrusions 56. If it
is not important that many or most of the protrusions 56 contain
openings, then the "well-aligned" characteristic discussed above
would not need to be maintained when constructing such
microstructures.
[0071] In conclusion, the present invention offers a method for
simultaneously creating openings and/or indentations in a moldable
material, while that moldable material is actually having its shape
formed and solidified. The present invention additionally offers a
method for constructing a micromold by depositing material (e.g.,
by electroplating, spin coating, or vapor deposition onto a tooling
structure having a predetermined shape, and then releasing the
deposited material, which will thereby have acquired the physical
shape that is a three-dimensional negative of the tooling
structure's physical shape.
[0072] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention.
[0073] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
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